The clear skies and bright sunshine that graced the opening three days of the 142nd Open were absent by the time the final round began to form a decisive shape.

As the majority of spectators alternated between the final two groups, Mickelson was steadily, and stealthily, winding his way through the field under a blanket of cloud on the East Lothian coast.

He reached the turn at two-under, by which time the frontrunners had begun to shed shots. Slowly but surely, the galleries got wind of his charge and made a beeline for Lefty.

It was the 13th where the momentum swung his way, a birdie putt sparking a run that was to end with him posing for photos with the Claret Jug as the main grandstand was enveloped in late afternoon gloom.

Another birdie on 14 moved him one shot behind then leader Scott, before two perfect blows to the par five 17th saw him infused with adrenalin as he seized the outright lead for the first time in the Championship.

By this time Scott had carded four consecutive bogeys, the same run that saw him relinquish the lead 12 months ago at Royal Lytham to allow South African Ernie Els to claim his second Open title.

Another Mickelson birdie on the final hole saw him punching the air, hugging his caddy Jim 'Bones' Mackay and breaking down as he realized he'd finally landed the one crown he wasn't sure his game was equipped to deliver.

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It was his second victory in a week after he won the Scottish Open and goes some way to repairing the desolation he felt after losing out on the U.S. Open crown to England's Justin Rose at Merion last month.

For home hoppe Westwood, the final day only served to reinforce the widely-held notion that his game isn't sturdy enough to close out a major championship.

Leading by two as he teed off in front of a supportive crowd at 2:10pm local time, he managed just one birdie and carded five bogeys.

It meant he ended a 62nd major without topping the leaderboard, extending an unwanted record that weighs heavily around his neck.

"I didn't play that badly -- probably not so well at seven, eight or nine," he explained to reporters.

"Phil must have played really well for five under par this afternoon, especially with a breeze going. That is a special finish in a major championship."

Woods too will rue missed opportunities as he goes in search of the 15th title that will end his half-decade without a major championship.

Three birdies were canceled out by six bogeys and he could only watch from the 14th green as, only 30 yards away, Mickelson marched up the 17th on his way to a pivotal birdie to a rapturous ovation from the crowd.

"It was frustrating. I played well," Woods told reporters. "I could just never get the speed right today.

"I had a hard time adjusting to the speeds. They were much slower today, much softer. I don't think I got too many putts to the hole today.

"I really had a hard time and left myself a couple of long lag putts early on when [the wind] was really blowing, and left them way short and didn't make those putts."